/mexico border southeast of tucson. they were investigating an alarm triggered by one of the many sensors along the border. no suspects has been identified. >>> american airlines said another plane had passenger seats that came loose during a flight. american says it happened last week on a flight to colorado from dallas/ft. worth. two other flights had similar problems this past week. american is inspecting its jets with similar seating. american officials say the loose seats are not an act of sabotage. >>> next in today's "news nation" gut check, how important is the upcoming presidential debate be in helping you decide who to support? that's one of the official questions, but you get to answer it now in gut check. we'll be right back and you can join the "news nation" on facebook at facebook.com/newsnation. my name is adam frucci and i'm the editor of splitsider.com. i love new technology, so when i heard that american express and twitter were teaming up, i was pretty interested. turns out you just sync your american